Switch and Motor-Cooling Device for an Electric Fan

ABSTRACT

A switch and a motor-cooling device for an electric fan comprise a motor, a housing, a controller and a knob. The housing is defined with a concave portion in an end thereof, and on the bottom of the concave portion are provided plural assembling portions. The concave portion is formed with an outward-enlarged arc-shaped guiding surface around a periphery thereof and interiorly defined with plural inlet holes. The controller and the knob are assembled to the assembling portions. The knob is exteriorly provided with a tapered arc-shaped guiding surface. With the guiding surface of the housing and the guiding surface of the knob, the air within the angular scope of the concave portion and behind the knob can be completely sucked into the concave portion, thus increasing the amount of the air sucked into the housing and obtaining the optimal heat dissipation efficiency.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a switch and a motor-cooling device foran electric fan, and more particularly to a switch for controllingON/OFF of the power supply and adjusting the speed of an electric fan

2. Description of the Prior Art

The existing switches and cooling devices for an electric fan aredivided into the following two types:

1. One type is as shown in FIG. 5, a switch for an electric fan isdisposed on a fan body (not shown) outside a housing 62, and a motor 61is disposed inside the housing 62. In order to dissipate the heatgenerated by the motor 61 and prevent the electric fan from blowing outhot air after a long time use of the motor 61, the housing 62 is definedwith plural air inlet holes 622 in a flat end surface 621 thereof.However, since the end surface 621 is too small, it is incapable oftaking in as much cooling air as needed, resulting in low heatdissipation efficiency. In addition, since the switch is disposed on thefan body outside the housing 62, operating the switch is inconvenientand needs the user to bend his back.

2. The other type is as shown in FIG. 6, a motor 71 for an electric fanis disposed in a housing 72, and a switch 73 is disposed at a distal endof a housing 72. The switch 73 is formed with a protruded arc-shaped endat the distal end of the housing 72. The housing 72 is defined withplural air inlet holes 721 around the outer periphery thereof. By sucharrangements, the area of the housing 72 for sucking cool air isincreased, the cool air behind the switch 73, however, cannot be suckedinto the housing 72. Therefore, improvements are needed. In addition,the arrangement of the air inlet holes 721 greatly increases the totallength of the assembly of the switch 73 and the housing 72, thusoccupying much space.

The present invention has arisen to mitigate and/or obviate theafore-described disadvantages.

SUMMARY OF THE INVENTION

The technical problems to be solved:

The existing switches and motor-cooling devices for an electric fan havelow heat dissipation efficiency due to the poor design of the air inletholes which cannot take in a large amount of cool air.

In order to solve the above technical problem, a switch and amotor-cooling device for an electric fan in accordance with the presentinvention comprise a motor, a housing, a controller and a knob. Themotor is connected to plural fan blades. The housing has one endconnected to the motor and an end cap and encloses the motor. The otherend of the housing is defined with a concave portion. On the bottom ofthe concave portion are provided plural assembling portions. The concaveportion is formed with an outward-enlarged arc-shaped guiding surfacearound the periphery thereof and interiorly defined with plural inletholes. The controller is assembled to the assembling portions in theconcave portion and further provided with an assembling rod. The knoband the controller constitute the switch of the present invention. Theknob is interiorly defined with an assembling hole to be assembled tothe assembling rod and exteriorly formed with a tapered arc-shapedguiding surface.

The present invention has the following advantages:

The housing is defined with the concave portion in the one end thereof,and the concave portion is formed with the outward-enlarged arc-shapedguiding surface on the periphery thereof and interiorly defined with theplural inlet holes, so the cool air within the angular scope of theoutward-enlarged circular guiding surface can be completely sucked intothe housing. In addition, although the concave portion is centrallyprovided with the knob, the knob is formed with the guiding surface toguide the air behind the knob to be sucked into the concave portion.Therefore, the amount of the air for cooling the motor is greatlyincreased, and the present invention can obtain the optimal heatdissipation efficiency.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view of a switch and a motor-cooling device foran electric fan in accordance with the present invention;

FIG. 2 is an exploded view of the switch and the motor-cooling devicefor an electric fan in accordance with the present invention;

FIG. 3 is a cross-sectional view of the switch and the motor-coolingdevice for an electric fan in accordance with the present invention;

FIG. 4 is a cross-sectional view illustrating how the air is sucked intothe concave portion of the housing of the present invention;

FIG. 5 is a cross-sectional view of a conventional switch and aconventional motor-cooling device for an electric fan; and

FIG. 6 is a cross-sectional view of another conventional switch andanother conventional motor-cooling device for an electric fan.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

The present invention will be clearer from the following descriptionwhen viewed together with the accompanying drawings, which show, forpurpose of illustrations only, the preferred embodiment in accordancewith the present invention.

Referring to FIGS. 1-3, a switch and a motor-cooling device for anelectric fan in accordance with the present invention comprise a motor10, a housing 20, a controller 30, and a knob 40.

The motor 10 is connected to plural fan blades 11.

The housing 20 has one end connected to the motor 10 and an end cap 100and encloses the motor 10. The other end of the housing 20 is definedwith a concave portion 21. On a bottom of the concave portion 21 areprovided plural assembling portions 22. The concave portion 21 is formedwith an outward-enlarged arc-shaped guiding surface 23 around aperiphery thereof. The concave portion 21 is further interiorly definedwith plural inlet holes 24. The housing 20 is further defined withplural air outlet holes 25 in the other end thereof below the concaveportion 21, as shown in FIG. 2.

The controller 30 controls the speed and ON/OFF of the motor 10 and isassembled to the assembling portions 22 in the concave portion 21. Thecontroller 30 is provided at both sides thereof with assembling portions31 to be assembled to the assembling portions 22 by screw. Thecontroller 30 is further provided with an assembling rod 32.

The knob 40 and the controller 30 constitute the switch of the electricfan of the present invention. The knob 40 is interiorly defined with anassembling hole 41 in a surface thereof which is located opposite thecontroller 30 in such a manner that the assembling hole 41 is assembledto the assembling rod 32. The knob 40 is exteriorly formed with atapered arc-shaped guiding surface 42. The guiding surface 42 isprovided with plural anti-slip portions 43 around a periphery thereof.

As shown in FIG. 4, with the above structure, when the electric fan isturned on to make the motor 10 drive the fan blades 11, the air will besucked into the concave portion 21 of the housing 20 and then enter thehousing 20 to absorb the heat of the motor 10 to cool the motor 10. Theair which has absorbed the heat of the motor 10 will be dischargedthough the air outlet holes 25. By such arrangements, the presentinvention has the following advantages: when being sucked into theconcave portion 21 of the housing 20, the air will move along theoutward-enlarged arc-shaped guiding surface 23 of the concave portion21. The air within the angular scope of the outward-enlarged arc-shapedguiding surface 23 will be completely sucked into the concave portion21, and even the air behind the knob 40 can also be sucked into theconcave portion 21 by cooperating with the guiding surface 42.Therefore, the amount of the air for cooling the motor 10 is greatlyincreased. In addition, the air which has absorbed the heat of the motor10 can be smoothly discharged from the air outlet holes 25. Therefore,the motor 10 can obtain the optimal heat dissipation efficiency.

While we have shown and described various embodiments in accordance withthe present invention, it is clear to those skilled in the art thatfurther embodiments may be made without departing from the scope of thepresent invention.

What is claimed is:
 1. A switch and a motor-cooling device for anelectric fan comprising: a motor being connected to plural fan blades; ahousing having one end connected to the motor and an end cap andenclosing the motor, the other end of the housing being defined with aconcave portion, on a bottom of the concave portion being providedplural assembling portions, the concave portion being formed with anoutward-enlarged arc-shaped guiding surface around a periphery thereof,and the concave portion being further interiorly defined with pluralinlet holes; a controller controlling a speed and ON/OFF of the motorand being assembled to the assembling portions in the concave portion ofthe housing, the controller being further provided with an assemblingrod; and a knob and the controller constitute the switch, the knob beinginteriorly defined with an assembling hole in a surface thereof which islocated opposite the controller and exteriorly formed with a taperedarc-shaped guiding surface.
 2. The switch and the motor-cooling devicefor an electric fan as claimed in claim 1, wherein the housing isdefined with plural air outlet holes in the other end thereof.
 3. Theswitch and the motor-cooling device for an electric fan as claimed inclaim 1, wherein the controller is provided at both sides thereof withassembling portions to be assembled to the assembling portions in theconcave portion of the housing by screw.
 4. The switch and themotor-cooling device for an electric fan as claimed in claim 1, whereinthe guiding surface of the knob is provided with plural anti-slipportions around a periphery thereof.